1. Field of the Invention
The present invention relates to an industrial material and more particularly to a perm-selective membrane for gases and liquids and a process for producing the same.
2. Related Art Statement
Conventional permselective membranes are roughly divided into those for gases and those for liquids. Oxygen-enriched membranes are investigated as permselective membranes for gases to improve the combustibility of gases and petroleum fuels. As permselective membranes for liquids, separation membranes for alcohol-water and separation membranes for oil-water are investigated.
However, permselective membranes known at present are produced mainly by coating a porous substrate with a polymer and the surface of the substrate is not smooth. Therefore, when a polymer film is thinned for increasing the selection efficiency, a large number of pinholes are formed, so that only a permselective membrane having a selection ratio of about 4 can be obtained, resulting in low selective-permeation efficiency. Accordingly, various methods are now investigated for raising the efficiency, but a membrane having a sufficient selective permeability has not yet been obtained.
On the other hand, it is known that a built-up film of monomolecular films of a linear hydrocarbon derivative having a chlorosilyl group (--SiCl.sub.x) at one terminal can be formed by forming monomolecular films of said derivative in an organic solvent on a hydrophilic substrate surface by chemisorption, and irradiating the monomolecular films with a high-energy beam in an oxygen-containing gas to make the films' surface hydrophilic.
However, there has not yet been proposed a process for producing a permselective membrane having a high selective-permeation efficiency by utilizing the technique described above.